Radio proximity fuze



Aug. 30, 1966 R. H. VARIAN 3,269,314

RADIO PROXIMITY FUZE Filed Dec. '7, 1942 2 Sheets-Sheet 1 l OSCILLATOR56 FILTER FILTER FILTER FILTER Fl LTEP FILTER PECT RECT RECT RECT RECTRELCT INVENTOR 4 RUSSELL. h. MGR/RN Y my ' ATTORNEY Aug. 30, 1966 R. H.VARIAN RADIO PROXIMITY FUZE Filed Dec. 7, 1942 7 a 3 1oi 1: 10 1o LTUNED UHF: OSCILLATING DETECTOR 2 Sheets-Sheet 2 INVENTOR A USSELLUnited States Patent 3,269,314 RADIO PROTY FUZE Russell H. Varian,Wantagh, N.Y., assignor to Sperry Rand Corporation, a corporation ofDelaware Original application July 8, 1941, Ser. No. 401,474. Dividedand this application Dec. 7, 1942, Ser. No. 468,308

2 Claims. (Cl. 102-702) This application is a division of Serial No.401,474, filed July 8, 1941, for Radio Controlled Projectiles, nowPatent No. 2,414,103.

This invention relates, generally, to the use of ultrahigh frequencyradio Waves for controlling bombs and other explosive missiles such asrocket missiles, aerial torpedoes, shells, etc., after the same havebeen discharged from their releasing or projecting apparatus and duringflight.

Owing to the constantly increasing height at which military aircraftnavigate, it is highly desirable to control explosive missiles such asbombs, aerial torpedoes, shells, rockets, etc., after they have left theairplane or the ground as the case may be, in order to correct for theinitial sighting errors and other errors including drift errors due tovariation of side winds at varying altitudes. Thus, in bombing a targeton the ground from an airplane, initial errors present at the time ofthe release of the bomb are generally augmented by the variations of thebomb trajectory due to such things as wobbling of the bomb, variation inthe wind direction and speed with changing altitude or change in thespeed or direction of movement of a moving target.

It is also very desirable to effect automatic detonation of explosivemissiles such as bombs, aerial torpedoes, shells, rockets, etc., whenthey arrive at the distance of closest approach to the target so thatdifiiculties commonly experienced in the use of time-delay fuses or thelike may be avoided. Among these difficulties are the considerations offiring range, time required for loading, and other known factors whichinfluence the computed time for the explosion calculated from the momentof discharge.

In accordance with the present invention, the detonation of the chargecarried by the missile is caused by an arrangement which is activated bythe mutual interaction of the missile and the target, and which isuniquely responsive to the arrival of the missile at its closestapproach to the target.

In one embodiment of the present invention, the effect is obtainedthrough the provision in the missile of means for projecting ultra highfrequency electromagnetic energy toward the target, and for receiving aportion of said energy reflected from the target, said means comprisingfrequency responsive means for effecting the detonation of the missilewhen the beat frequency between the projected and the received energiesreaches a predetermined value.

In another form of the present invention, the missile is provided withmeans for directly receiving ultra high frequency energy projected froma source removed from the missile and for receiving energy from saidsource after reflection thereof from the target, and frequencyresponsive means coupledto said receiving means for detonating themissile when the beat frequency between the directly received energy andthe reflected energy reaches a predetermined value.

The principal object of the present invention is to provide novelapparatus for bombs and other explosive projectiles such as rocketmissiles, aerial torpedoes, shells, rockets, etc., whereby said missilesare automatically detonated and caused to explode when said missilesarrive at substantially their nearest approach to a target.

Another object of the present invention is to provide an ultrahighfrequency transmitter adjacent the point at which the bomb or othermissile is released, the missile being equipped with suitable ultra-highfrequency radio receiving apparatus and means coupled to said apparatusfor detonating the missile when the latter and a selected target are ina predetermined spatial relationship.

Another object of the invention lies in the provision of means foreffecting automatic detonation of the missile when the same has reachedthe distance of closest approach to the target.

Still another object of the present invention is the provision of amissile with oscillating detector means for producing electromagneticenergy and for receiving such energy as reflected from the target, thesaid means serving to effect the detonation of the missile when anydesired beat frequency is reached between the transmitted and receivedenergy.

Other objects and advantages will become apparent from thespecification, taken in connection with the accompanying drawingswherein the invention is embodied in concrete form.

In the drawings:

FIG. 1 is a scchematic view illustrating one use of the apparatus of thepresent invention.

FIG. 2 is a vertical part sectional view of a transmitter opticalsighting and energy radiating means.

FIG. 3 is a longitudinal cross sectional view showing a missile equippedwith flight control and automatic detonating means in accordance withthe present invention.

FIG. 4 is a sectional view along 44 of FIG. 3; and

FIG. 5 is a wiring diagram of a somewhat modified structure.

Similar characters of reference are used in all of the above figures toindicate corresponding parts.

Referring now to FIG. 1, reference numeral 1 designates an airplaneequipped with one form of the transmitter apparatus with which themissile of the present invention may be employed. This craft is adaptedto carry an ultra-high frequency oscillator 2 as of the type disclosedin Patent No. 2,242,275, of R. H. Varian, dated May 20, 1941, fordelivering to an aerial transmitter antenna assembly 3, ultra-highfrequency carrier waves of the order of 10 cycles per second, such wavesbeing subject to propagation in substantially straight lines and alsohaving the property of penetrating fog, etc. and not being appreciablyinterfered with by uncontrollable natural phenomena such as radiationfrom the sun. The antenna assembly 3 is shown in detail in FIG. 2 andcomprises a parabolic reflector 4 which has a diameter preferably twentyor more times the wavelength used, whereby this reflector has highresolving power and produces a highly directional beam ofelectromagnetic energy. A radiator element 3' is supported at the focusof the reflector 4. The reflector 4 and element 3 are shown as carriedby the lower end of a telescope 5 that has its line of vision coaxialwith that of the electromagnetic radiation beam shown diagrammaticallyat 27 in FIG. 1 and and projected from the antenna assembly 3. Thetelescope 5 is universally mounted as by means of a ball joint 6 so thatthis telescope and the connected transmitter antenna may be turned toany desired angle.

In the event of bombing through the overcast, the telescope 5 needmerely be used as an angular shifting means for turning the antennaelement 3' and reflector 4, the information used for then directing thebeam being obtained from any suitable radio direction and rangeindicating system. The ultra-high frequency radio output of thetransmitter antenna assembly 3 is adapted to be received by fourantennae 7, 7', 8, 8' carried by a missile 9 illustrated in FIG. 3.

Antennae 7, 7' are spaced an appreciable distance apart as by placingthese antennae on the outer edges of opposed fins 10. Similarly, theantennae 8, 8 (antenna 8 not shown) are spaced appreciably apart as bybeing located on the outer edges of fins 10' extending at right anglesto the plane of fins 10 carrying antennae 7, 7

The form of the missile illustrated in FIG. 3 is generally similar tomissiles in general use for bombing from aircraft. However, thestabilizing fins 10, 10' are shown extending radially outward from thecylindrical body of missile 9, whereas the conventional form of missileused for bombing comprises fins somewhat farther astern of the main bodyof the missile and of no greater radial extent than the cylindrical bodyof the bomb. Either the form shown in FIG. 3 or the conventional form ofbombing missile is suitable for use with the present invention in themanner of installation shown in FIG. 3. The latter form-the conventionalbomb--is readily adapted to be propelled from a cannon, if desired, inpreference to the form of FIG. 3, which is shown with disproportionatelyextensive stabilizing fins for clarity of illustration of the invention.

In the form of missile shown in FIG. 3, or the conventional form in useas a bomb, the antennas 7, 7' 8, 8 may be mounted on the outerextremities of the stabilizing fins.

In the form of missile conventionally used for bombing, the smoothcylindrical surface wihch defines the maximum radial extent of the bomb,adapts the missile to be projected from a smooth bore cannon.Furthermore, similar missiles having substanitally cylindrical bodiesand relatively small stabilizing fins are used as rocket projectiles,being discharged from tubes or guns used for directing the rocketmissiles toward a target.

In FIG. 3 the antennae 7, 7' are shown as dipoles connected throughconcentric lines 11, 11 to suitable impedance matching transformers 12,12' of the type disclosed in Patent No. 2,406,372, dated August 27,1946, Hansen et al. which in turn supply the received energy to crystaldetectors 13, 13 of the type disclosed in Patent No. 2,406,- 405, datedAugust 27, 1946, F. L. Salisbury. The detected outputs of crystaldetectors 13, 13' are supplied to amplifiers 14, 14' the outputs ofwhich are shown supplied through rate circuits 15, 15'. If desired, therate circuits 15, 15' could be omitted. Inasmuch as the particular typeof matching transformers 12, 12 or crystal detectors 13, 13' or ratecircuits 15, 15' here employed form no part of the present invention, afuller description of these components is not deemed necessary. Anyconventional elements of these types may be used here. The outputs ofthe rate circuits 15, 15 are connected respectively to solenoids 16, 16'arranged for opposite actuation of armatures 19, 19' connected to apiston 17 of a balanced valve 18. The central portion of valve 18 issupplied with compressed air or carbon dioxide gas from a tank 20through pipe 23. When carbon dioxide is used it may be carried in liquidform in tank 20. Valve 18 has two upper pipes 21 and 21 that have theirouter portions extending radially within the cylindrical body of themissile 9 in opposite directions, the common axis of these portions ofthe pipes 21, 21' passing preferably through the center of gravity ofthe missile. The outer ends of the pipes 21, 21' project through thehousing of the missile for delivering compressed air or carbon dioxidegas in opposite directions diametrically of the missile. The radialportions of pipes 21 and 21' lie in the vertical plane also containingthe spaced antennae 7 and 7'.

The antennae 8 (and 8 are similarly connected to a receiver circuit,such as shown in FIG. 3, for controlling the operation of solenoids 22and 22, shown in FIG. 4, the armatures of these solenoids being employedfor operating the balanced valve 18' similar to valve 18, valve 18controlling the flow of compressed air from the pipe 23 to two outwardlyextending pipes 24 and 24' extending through the wall of the missile 9for directing air or carbon dioxide blasts in diametrically oppositedirections. The radial portions of pipes 24 and 24 lie in the plane ofantennae 8, 8.

In use, preferably a suitable bomb sight is provided on the aircraftsuch as that disclosed in Patent No. 2,162,698, dated June 20, 1939, andis employed for releasing the missile 9 at the proper time and in theproper direction for hitting the target desired. After releasing themissile and before the same has reached its target the bombardier looksthrough the telescope 5 and observes the falling missile. To aid him inobserving the missile, the same may be provided with a lamp 25, ifdesired. Inasmuch as the forward velocity of the missile decreasesgradually after release thereof due to air friction the bombardier wouldordinarily direct the pilot to reduce speed so that the aircraft fliesover the target at about the same time as the predicted time for themissile to strike the same. This change in speed of the airplane makesthe same an extremely difficult target to hit from a point such as theship 26, shown in FIG. 1, inasmuch as all predictions are based upon thecraft maintaining a fixed speed.

It is preferable for the bombardier to keep the target or point in sightthrough the telescope 5 as the missile falls. As the missile approachesthe target, the latter moves into the field of vision of the bombardierlooking down through the telescope 5 although the target is probably notin the central line of sight of the telescope at this time. If theoscillator 2 is now turned on producing the pencil beam 27 of ultra-highfrequency electromagnetic radiation the field intensity of any crosssection of which is greatest at the center 27' of the beam and tapersoff in substantially the fashion shown toward the side edges thereof,the missile will ordinarily line itself up with the center 27' of thebeam. Assuming that the missile is not initially lined up with thecenter of the beam then due to the varying field intensity of the beamacross its cross section one of the antennae 7 or 7', for example, willreceive more energy than the other, so that the output of amplifier 14,for example, will be made greater than that of amplifier 14, wherebysolenoid 16 is energized to a greater extent than solenoid 16 so thatthe balanced valve 17 is moved to uncover pipe 21 thereby causing tank20 to discharge compressed air or gas through valve 18 and pipe 21 andelfecting a movement of the bomb toward the center of the radiatingbeam. Similarly, if antenna 8, for example, should receive more energythan antenna 8' it would act to shift the bomb transversely in the planeof these antennae to bring the bomb into the central axis 27 of theradiating beam corresponding to the center of the line of sight of thetelescope 5. As the missile is about to strike the target the bombardiergradually shifts the telescope 5 angularly so as to bring his line ofsight and hence the missile into the direct line of the target so thatthe latter will be hit as desired.

It will be noted that as long as the missile is lined up with the center27' of the radiating electromagnetic beam, the antennae 7, 7 and 8, 8'will receive equal intensity of signal so that the balanced valves 18,18' will be held in their neutral positions so that the outputs of thevarious amplifiers will be equal. Should the missile commence to moveout of the center of the beam the antennae will receive signals ofunequal strength resulting in the operation of the servo-mechanism andthe movement of the missile transversely back into the center of theradiating beam. Owing to the high pressure of the air or gas within thetank and to the fact that the period of time of flight of the bomb isshort, the flow of air or gas through pipes 21, 21' and 24, 24' is quiterapid so that the reaction force of the jets issuing from these pipes islarge, thereby resulting in an immediate response of the missile to anydeviation of the same from the path of the beam effecting a rapid returnof the missile to the beam. Should the bombardier move his telescope 5angularly too rapidly so as to lose the missile he can always turn thesame back and pick the missile up again.

The flight controlled missile and radio energy transmitting apparatusemployed therewith has thus far been described for the purpose ofproviding a vehicle and control for the automatic detonating devicepresently to be described. It is to be understood, however, that thisparticular type of missile and/or radio energy transmitting apparatushas been selected for this purpose merely as an illustrative example andtherefore should not be regarded as a limitation on or restriction ofthe application or use of the automatic detonator. Other types oftransmitting apparatus producing, for example, I3. plurality of ultrahigh frequency electromagnetic energy beams instead of the single beam,heretofore described, may be employed with a missile carrying adifferent type of receiving apparatus adapted to respond to theplurality of beams for the purpose of following the path determinedthereby. This and other forms of missiles and transmitting systemscorresponding thereto are described in the above-mentioned parentapplication Serial No. 401,474 and may be utilized as the vehicle forthe present invention in place of the radio energy transmittingapparatus and flight controlled missile hereinabove described.

In the form of the invention shown in FIG. 3 the missile 9 is providedwith means for effecting the detonation thereof when the missile hasreached a predetermined position with respect to the target. In thisfigure an ultra high frequency oscillating detector 30, which in thetype disclosed in No. 2,406,370 in which the present applicant is ajoint patentee, comprises a velocity modulation electronic device havinga pair of electronbeam-coupled cavity resonators, means for radiatingand receiving electromagnetic energy, and detector means for detectingand beating energy returned to the device by reflection of the radiatedenergy, from a target, with a part of the energy radiated, is employedherein having a connected antenna 32 which serves to transmit the outputof this oscillating detector and to receive waves reflected from thetarget. Owing to the Doppler effect, the beat frequency between theoutput of the oscillating detector and the frequency received thereby isproportional to the relative velocities between the target and theprojectile and since the relative velocity at closest approach is zerothe Doppler frequency at such point will drop to zero. By having anaudio amplifier 34, as of the type described in Termans RadioEngineering, published by McGraw-Hill Book Company, second edition, page210, connected to the output of oscillating detector 30, tuned to adesired frequency the missile may be made to detonate at any desiredposition with respect to the target as the same advances toward thetarget. The output of amplifier 34 is fed through a wire 36 which servesto detonate the charge 38 at the desired point.

In the form of the invention shown in FIG. 5 the missile is not providedwith a local oscillating detector but instead is provided with an ultrahigh frequency detector 40 fed from the antenna 42 the output of whichdetector is fed through the audio amplifier 44 to a series of filters 46to 56 which filters have progressively higher band pass frequencies. Theoutputs of these filters are supplied to rectifiers 58 to 68,respectively, the output of which rectifiers in turn are adapted tooperate relays 70 to 80, respectively. In operation, if the missileapproaches a rapidly moving target the Doppler frequency produced byreceipt by antenna 42 of the direct radiation from the transmitter 2 inFIG. 1 and that received by reflection from the target will decrease asthe missile approaches the target so that a point is reached for arapidly approaching target where filter 56 will pass current, therebyoperating relay and preparing a circuit for relay 74. As the missileapproaches closer to the target filter 50 will finally pass currentenergizing relay 74 and effecting the detonation of the charge 82. Onthe other hand, if the target is not as rapidly approaching, it is quitepossible that the Doppler frequency will be lower than that passed byfilter 56 so that the lower band pass filter 54 will energize relay 78thereby preparing a circuit for relay 72 which, when closed by thepassage of current by filter 48, i.e., when the missile is in theproximity of the target, then the charge 82 will be detonated. Theoperation of filters 52 and 46 is similar and applicable to even slowerapproaching targets or to receding targets.

It will be noted that since no oscillator is employed on the projectile,the Doppler frequency obtaining, which is a beat between directlyreceived and reflected waves, does not reach zero, at closest approachand hence the necessity for the use of filters as shown in FIG. 5

It will be understood that the missile launching apparatus hereinillustrated as the airplane 1 is merely exemplary and indicative of onetype of apparatus which may be so employed. If desired, the missile maybe launched from the ground as by a gun, catapult, rocket tube, or anyother type of missile launching apparatus or platform.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In apparatus of the character described, a missile adapted to bepropelled toward a target, means for directing electromagnetic radiationat said missile and from the target, said missile having a receiver forreceiving the direct radiation from said radiating means and forreceiving radiation reflected from the target, a normally opendetonation control circuit in said missile, and frequency selectivemeans controlled from said receiver for effecting the closing of saiddetonation circuit when a predetermined heterodyne frequency is producedin said receiver by said direct reception and said reflected reception.

2. A projectile as defined in claim 1 wherein said frequency selectivemeans comprises a plurality of filters of progressively differing bandpass frequencies and relays controlled from said filters, saiddetonation circuit comprising a connection between a relay operated at acertain frequency with a relay operating at a higher frequency.

References Cited by the Examiner UNITED STATES PATENTS 1,386,459 8/1921Dawson et al. 89--41 1,769,203 7/ 1930 Buckley 1029 X 1,862,918 6/1932Barnes 89-41 2,022,517 11/ 1935 Patterson.

2,066,156 12/1936 Mufliy 177-352 2,137,598 11/1938 Vos 10270.2

(Other references on following page) UNITED 7 STATES PATENTS Koch 250-2Ferrell 10270.2

Crooke 89-41 FOREIGN PATENTS Austria. France. Great Britain. GreatBritain.

8 524,876 8/ 1940 Great Britain. 339,479 4/1936 Italy.

91,592 2/1938 Sweden.

BENJAMI'N A. BORC'I-IELT, Primary Examiner.

0 H. L. MARTIN, L. H. MEYERS, W. C. ROCH,

1 Assistant Examiners.

1. IN APPARATUS OF THE CHARACTER DESCRIBED, A MISSILE ADAPTED TO BEPROPELLED TOWARD A TARGET, MEANS FOR DIRECTING ELECTROMAGNETIC RADIATIONAT SAID MISSILE AND FROM THE TARGET, SAID MISSILE HAVING A RECEIVER FORRECEIVING THE DIRECT RADIATION FROM SAID RADIATING MEANS AND FORRECEIVING RADIATION REFLECTED FROM THE TARGET, A NORMALLY OPENDETONATION CONTROL CIRCUIT IN SAID MISSILE, AND FREQUENCY SELECTIVEMEANS CONTROLLED FROM SAID RECEIVER FOR EFFECTING THE CLOSING OF SAIDDETONATION CIRCUIT WHEN A PREDETERMINED HETERODYNE FREQUENCY IS PRODUCEDIN SAID RECEIVER BY SAID DIRECT RECEPTION AND SAID REFLECTED RECEPTION.